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Michael Macari

Publications and source records attributed to Michael Macari.

18 recordsLinked to original sources
PubMed2005

Type II endoleaks after endovascular repair of abdominal aortic aneurysms: natural history.

PURPOSE: To retrospectively determine the natural history of type II endoleaks detected at thin-section multi-detector row computed tomographic (CT) angiography. MATERIALS AND METHODS: Neither institutional review board approval nor patient informed consent was required. Between December 1999 and December 2000, 83 patients (73 men and 10 women; mean age, 61 years; range, 55-75 years) underwent endovascular repair of an infrarenal abdominal aortic aneurysm with an endoluminal stent graft. Postprocedural abdominal CT angiography was performed every 3-12 months for the evaluation of endoleaks and the maximal sac diameter. A retrospective analysis of all postprocedural CT angiographic reports was performed until November 2003 to document the presence and development of type II endoleaks and the maximal orthogonal aneurysmal sac size. Findings at CT angiography were evaluated with regard to clinical outcomes and treatment in all patients in whom type II endoleaks were observed. The postprocedural follow-up period was 1.5-4.5 years (mean, 2.5 years). RESULTS: Twenty type II endoleaks were identified in 16 (19%) of the 83 patients. Four (20%) of the 20 endoleaks were embolized secondary to an increasing aneurysmal sac size when compared with that at preoperative CT angiography. These four leaks occurred in two patients, each with two separate endoleaks. Sixteen (80%) of the 20 endoleaks in 14 patients were managed with continued observation. In these patients, the aneurysmal sac size was stable or had decreased when compared with the size at preoperative CT angiography. Ten (62.5%) of the 16 endoleaks have sealed spontaneously during the follow-up, and six (37.5%) have persisted with stable or decreased aneurysmal sac size. None of the patients experienced aneurysmal sac rupture. CONCLUSION: Type II endoleaks with a stable or decreased aneurysmal sac size can be followed up with CT angiography secondary to the high rate of spontaneous resolution and a low risk of rupture.

Aged↗
PubMed2005

Stercoral colitis leading to fatal peritonitis: CT findings.

OBJECTIVE: Stercoral colitis is an inflammatory process involving the colonic wall related to fecal impaction. Our purpose was to describe the imaging findings of stercoral colitis and ulceration and to emphasize the potential serious clinical implications of the condition. CONCLUSION: Fecal impaction may lead to ischemic pressure necrosis and subsequent colonic perforation. In the appropriate clinical setting, the imaging findings that should prompt the radiologist to consider this diagnosis are the presence of fecal impaction, focal colonic wall thickening, and adjacent stranding of the fat. If the fecal impaction is not promptly relieved, the condition can lead to colonic perforation, peritonitis, and patient demise.

Aged↗
PubMed2004

Virtual colonoscopy.

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Colonography, Computed Tomographic↗
PubMed2004

Colorectal polyps and cancers in asymptomatic average-risk patients: evaluation with CT colonography.

PURPOSE: To compare thin-section multi-detector row computed tomographic (CT) colonography with conventional colonoscopy in the evaluation of colorectal polyps and cancer in asymptomatic average-risk patients. MATERIALS AND METHODS: Sixty-eight asymptomatic men (age > 50 years) scheduled to undergo screening colonoscopy were enrolled in this study. CT colonography was followed by conventional colonoscopy, performed on the same day. Supine and prone CT colonography were performed after colonic insufflation with room air. A gastroenterologist measured all polyps, which were categorized as 1-5, 6-9, or over 10 mm. Biopsy and histologic evaluation were performed of all polyps. CT colonography and colonoscopy results were compared for location, size, and morphology of detected lesions. Point estimates and 95% CIs were provided for specificity and sensitivity of CT by using results at conventional colonoscopy as the reference standard. RESULTS: At colonoscopy, 98 polyps were identified in 39 patients; 21 (21.4%) of 98 were detected at CT colonography. Sensitivity was 11.5% (nine of 78) for polyps 1-5 mm, 52.9% (nine of 17) for polyps 6-9 mm, and 100% (three of three) for polyps over 10 mm. Results at colonoscopy were normal in 29 (42.6%) of 68 patients; at CT colonography, results were correctly identified as normal in 26 of these 29 patients. In one of these patients, a lesion larger than 10 mm was detected at CT colonography. The per-patient specificity of CT was 89.7% (26 of 29; 95% CI: 72.7%, 97.8%). The mean time for CT image interpretation was 9 minutes. CONCLUSION: In patients at average risk for colorectal cancer, CT colonography is a sensitive and specific screening test for detecting polyps 10 mm or larger; the sensitivity for detecting smaller polyps is decreased. Examination findings can be interpreted in a clinically feasible amount of time.

Animals↗
PubMed2004

Prevalence and impact of extracolonic findings in patients undergoing CT colonography.

BACKGROUND: CT colonography (virtual colonoscopy) is a new technique being offered to patients as a noninvasive method of imaging the colon. The aims of this study were to prospectively determine the prevalence of extracolonic findings in patients undergoing CT colonography, as well as to determine the clinical significance and consequences of these findings. METHODS: Two-hundred and fifty patients who were referred for colonoscopy for clinically indicated reasons underwent CT colonography using low-dose radiation (50 mAs) immediately prior to conventional colonoscopy. A single radiologist reviewed the CT images for extracolonic pathology, and findings were classified as having high, moderate, or low clinical significance. Electronic medical records were reviewed to assess what follow up diagnostic tests, if any, were performed. RESULTS: A total of 136 extracolonic findings were detected in 83 (33.2%) of the 250 patients. Of these 136 findings, 17 (12.5%) were highly significant, 53 (38.9%) were moderately significant, and 66 (48.5%) were of low significance. The most common highly significant lesions were solitary lung nodules in 3 patients, mesenteric lymphadenopathy in 3, adrenal masses in 2, low attenuation liver lesions consistent with metastases in 2, and bone metastases in 2 patients. Fourteen of the 17 (82.4%) highly significant findings were new findings, and in 11 the extracolonic abnormalities resulted in further diagnostic testing. None of the patients with moderate or low significance lesions underwent further testing. CONCLUSIONS: Low-dose CT colonography can detect highly significant extracolonic findings. Although extracolonic lesions were common, only a small proportion of patients required further diagnostic testing. Additional studies to determine the optimal radiation dose, cost-effectiveness, and legal implications of detecting extracolonic findings are warranted.

Aged↗
PubMed2004

Positional change in colon polyps at CT colonography.

PURPOSE: To determine the frequency with which polyps change positions with respect to the bowel surface and the cause of this movement. MATERIALS AND METHODS: From December 2001 to March 2003, 113 patients underwent computed tomographic (CT) colonography prior to colonoscopy. For all confirmed polyps that were 5 mm and larger, images obtained with CT colonography were retrospectively analyzed by one author to determine if the polyp was present on both data sets or on only one data set. Retrospective evaluation of these polyps for ventral or dorsal location within the colonic lumen was performed for data sets obtained with patients in the prone and the supine position. The data sets were further reviewed by another author to determine the cause of positional change, when present. RESULTS: Twenty-six patients had a total of 49 histologically proved colorectal polyps that were 5 mm and larger. Eight of 49 colorectal polyps were depicted only on images obtained with the patient in the supine or prone position. Of the remaining 41 polyps that were depicted on images obtained with the patient in the supine and the prone position, 11 moved from a dorsal to a ventral location or vice versa relative to the colonic surface when the patient changed position. Five of these polyps were pedunculated on a stalk. Six were sessile; two were located in the sigmoid colon, two in the transverse colon, one in the ascending colon, and one in the cecum. In these cases, polyp mobility was related to positional changes of the colon in the mesentery, as opposed to true mobility of the polyp. CONCLUSION: In this series, 27% of polyps moved from a ventral location to a dorsal location relative to the colonic surface when the patient was turned from the supine to the prone position; thus, polyps appeared to be mobile. Thus, a mobile filling defect cannot be assumed to be residual fecal material at CT colonography.

Aged↗
PubMed2004

Significance of missed polyps at CT colonography.

OBJECTIVE: Our purpose was to determine the clinical significance of polyps missed on CT colonography using histologic analysis and the natural history of colorectal polyps and to propose guidelines for follow-up colon surveillance based on CT colonographic findings. SUBJECTS AND METHODS. One hundred eighty-six men (age range, 40-87 years; mean, 62.3 years) underwent CT colonography immediately before conventional colonoscopy. All polyps detected on CT colonography were measured and imaged, and their segmental location was documented. All polyps detected on colonoscopy were measured, photographed, biopsied, and histologically analyzed. Results of CT colonography and conventional colonoscopy were compared with the final pathology reports. Conventional colonoscopy was used as the gold standard unless CT colonography showed a lesion measuring 10 mm or more that was not detected on conventional colonoscopy and had characteristics of a polyp. In these cases, follow-up conventional colonoscopy was offered. RESULTS: One hundred ninety-one polyps were detected on conventional colonoscopy. CT colonography prospectively detected 53 polyps. Histologic analysis of the polyps not detected on CT colonography showed that of those 5 mm or smaller, 58.1% were not adenomas, and of those measuring 6-9 mm, 42.8% were not adenomas. Both missed polyps at CT colonography of 10 mm or more were adenomas. Of the 22 polyps measuring 10 mm or more, three were not detected on conventional colonoscopy. Of these three, CT colonography showed a lesion having characteristics of a polyp, follow-up endoscopy confirmed the presence of the lesion, and histologic analysis showed a villous adenoma, a tubulovillous adenoma, and a tubular adenoma. CONCLUSION: If CT colonography shows no abnormality, follow-up screening in 5 years is recommended. If CT colonography detects a lesion smaller than 5 mm, follow-up imaging in 3-5 years is recommended. If CT colonography detects a lesion measuring 6 mm or more, endoscopy and polypectomy should be offered unless contraindicated.

Colonic Polyps↗
PubMed2004

Frequency and relevance of the "small-bowel feces" sign on CT in patients with small-bowel obstruction.

OBJECTIVE: We sought to determine the incidence of the "small-bowel feces" sign (SBFS) in patients with small-bowel obstruction (SBO) and whether it can be used to accurately locate the point of obstruction. SUBJECTS AND METHODS: From November 2002 until March 2003, 34 consecutive adult patients with CT findings of small-bowel obstruction were prospectively evaluated. The CT findings used to diagnose small-bowel obstruction were a dilated proximal small bowel and a collapsed distal small bowel and colon. CT scans were evaluated to determine the degree of obstruction (mild, moderate, or high-grade), the presence or absence of the SBFS (defined as particulate-type material in the dilated small bowel), the location of the SBFS in relation to the transition zone, and the cause of the obstruction. Mild obstruction was defined as a slight discrepancy between the caliber of the proximal and that of the distal small bowel; moderate SBO was defined as a discrepancy of 50% or more between the calibers of the proximal and the distal small bowel; and high-grade SBO was considered to be present if the distal small bowel and the colon had collapsed. The cause of the obstruction was determined from surgical findings or a combination of CT findings, follow-up barium studies, and clinical assessment. RESULTS: The SBFS was present in 19 (55.9%) of 34 patients with SBO. The degree of SBO was mild in six, moderate in 11, and high-grade in 17 of the patients. The SBFS was present in one of the six patients (16.6%) with mild, eight (72.7%) of the 11 with moderate, and 10 (58.8%) of the 17 with high-grade SBO. In all patients in whom the SBFS was present, the particulate material could be traced to the point of transition and was most conspicuous in the transition zone. The length of fecallike material ranged from 2 to 25 cm and was longer in moderate and high-grade SBO than in mild SBO. The cause of the SBO was an adhesion in 20 patients, a hernia in four patients, Crohn's disease in four patients, a tumor in three patients, and other miscellaneous causes in three patients. CONCLUSION: When present on CT, the SBFS can be used to help locate the transition zone in patients with SBO. The sign is present more frequently in patients with moderate and high degrees of SBO.

Adult↗
PubMed2003

CT colonography data interpretation: effect of different section thicknesses--preliminary observations.

PURPOSE: To evaluate if differences exist in the interpretation of thin- and thick-section reconstructions at computed tomographic (CT) colonography. MATERIALS AND METHODS: Twenty-five patients underwent multi-detector row CT colonography prior to colonoscopy. CT images were reconstructed with two methods: 1.25-mm sections reconstructed every 1 mm (thin) and 5-mm sections reconstructed every 2 mm (thick). Two independent readers interpreted thin sections, then waited a minimum of 15 days before interpreting thick sections. With colonoscopy as the reference standard, comparisons were made between interpretation of thin and thick sections, including sensitivity, specificity, and number of false-positive observations. Interpretation times were recorded, and comparisons were made by using repeated measures analysis of variance. For all tests, P <.05 indicated a statistically significant difference. RESULTS: At colonoscopy, 10 patients had 12 polyps (< or =5 mm, n = 7; 6-9 mm, n = 2; > or =10 mm, n = 3). Sensitivity for polyp detection was statistically indistinguishable for thin and thick sections. Reader 1 had three false-positive findings with thin sections and six with thick sections. Reader 2 had six false-positive findings with thin sections and 11 with thick sections. For both readers, the number of false-positive findings was significantly lower for thin sections than for thick sections (P =.035). Specificity was 93.3% with thin sections and 80.0% with thick sections for reader 1 and 80.0% with thin sections and 73.3% with thick sections for reader 2. Mean interpretation time for reader 1 was significantly longer with thin sections (P <.001). Mean interpretation time for reader 2 was 13.0 minutes for both thin and thick sections. CONCLUSION: Specificity improved for both readers with thin sections, with no difference in sensitivity.

Aged↗
PubMed2003

Computerized tomographic colonography: performance evaluation in a retrospective multicenter setting.

BACKGROUND & AIMS: No multicenter study has been reported evaluating the performance and interobserver variability of computerized tomographic colonography. The aim of this study was to assess the accuracy of computerized tomographic colonography for detecting clinically important colorectal neoplasia (polyps >or=10 mm in diameter) in a multi-institutional study. METHODS: A retrospective study was developed from 341 patients who had computerized tomographic colonography and colonoscopy among 8 medical centers. Colonoscopy and pathology reports provided the standard. A random sample of 117 patients, stratified by criterion standard, was requested. Ninety-three patients were included (47% with polyps >or=10 mm; mean age, 62 years; 56% men; 84% white; 40% reported colorectal symptoms; 74% at increased risk for colorectal cancer). Eighteen radiologists blinded to the criterion standard interpreted computerized tomography colonography examinations, each using 2 of 3 different software display platforms. RESULTS: The average area under the receiver operating characteristic curve for identifying patients with at least 1 lesion >or=10 mm was 0.80 (95% lower confidence bound, 0.74). The average sensitivity and specificity were 75% (95% lower confidence bound, 68%) and 73% (95% lower confidence bound, 66%), respectively. Per-polyp sensitivity was 75%. A trend was observed for better performance with more observer experience. There was no difference in performance across software display platforms. CONCLUSIONS: Computerized tomographic colonography performance compared favorably with reported performance of fecal occult blood testing, flexible sigmoidoscopy, and barium enema. A prospective study evaluating the performance of computerized tomography colonography in a screening population is indicated.

Colonic Neoplasms↗
PubMed2003

The acute right lower quadrant: CT evaluation.

Acute right lower quadrant pain is a nonspecific but common clinical complaint. Appendicitis is the most common cause of acute right lower quadrant pain and CT has become the most reliable imaging method in the evaluation of these patients. Although there is controversy regarding the best way to perform CT in this setting, oral and i.v. contrast-enhanced CT remains the most commonly used technique. CT with oral and i.v. contrast material facilitates diagnosis of appendicitis and the numerous other entities that may cause right lower quadrant pain.

Abdomen, Acute↗
PubMed2003

Intestinal ischemia versus intramural hemorrhage: CT evaluation.

OBJECTIVE: We evaluated the capability of CT to depict findings that allowed differentiation of small-bowel ischemia from intramural hemorrhage. MATERIALS AND METHODS: Findings of 35 CT examinations (19 patients with small-bowel ischemia and 16 patients with intramural hemorrhage) were analyzed by two abdominal radiologists for the degree of wall thickening, location and length of involvement (short, 30 cm), presence of hemoperitoneum, and pattern of attenuation. Patency and caliber of the superior mesenteric artery and vein were noted. Diagnosis was confirmed by laboratory findings, clinical parameters, and follow-up examinations, or at surgery. A Mann-Whitney U or Fisher's exact test was used to compare the two conditions for the following features: wall thickening, location and length of involvement, presence of hemoperitoneum, and appearance of the target sign. RESULTS: Among the 35 examinations, 18 abnormal segments with intramural hemorrhage and 19 abnormal segments with ischemia were identified. (Two patients with intramural hemorrhage each had two segments involved.) Mean bowel wall thickness was 11.7 mm (range, 4-25 mm) in patients with intramural hemorrhage and 4.0 mm (range, 1-9 mm) in patients with ischemia. Length of involvement was short in 14 segments with intramural hemorrhage and medium in four segments with intramural hemorrhage; none of the segments with intramural hemorrhage had long involvement. Among the segments with ischemia, length of involvement was medium in three and long in 16; none of the ischemic segments had short involvement. Fifteen (94%) of 16 segments with intramural hemorrhage and six (32%) of 19 segments with ischemia had hemoperitoneum. Seven of the 18 segments with intramural hemorrhage and nine of the 19 with ischemia had a target sign. Segments with intramural hemorrhage exhibited a higher statistically significant degree of wall thickening (p < 0.001), a shorter length of involvement (p < 0.0001), and a higher incidence of hemoperitoneum (p < 0.001) than did segments with ischemia. The two groups were not statistically different in location of involvement (p = 0.12) or in the incidence of the target sign (p = 0.18). CONCLUSION: Although some of the CT features overlap, a short segment involvement with wall thickening of 1 cm or greater is typical of intramural hemorrhage; a long segment involvement with wall thickening of less than 1 cm is typical of ischemia.

Aged↗
PubMed2003

Duodenal diverticula mimicking cystic neoplasms of the pancreas: CT and MR imaging findings in seven patients.

OBJECTIVE: Duodenal diverticula are common and are typically asymptomatic. When filled with gas or a combination of fluid and gas, duodenal diverticula are easily recognized on CT or MR imaging. However, a duodenal diverticulum that is entirely filled with fluid may mimic a cystic neoplasm arising from the head of the pancreas. We present seven cases of patients with duodenal diverticula in whom initial findings on CT or MR imaging were suggestive of a cystic neoplasm in the head of the pancreas. In all patients, this structure was ultimately proven to be a duodenal diverticula. CONCLUSION: When filled with only fluid, a duodenal diverticulum may mimic a cystic neoplasm in the head of the pancreas. Recognizing the location in which this entity characteristically arises and identifying small amounts of intradiverticular gas when it is present may aid in establishing the correct diagnosis in patients with duodenal diverticula.

Aged↗
PubMed2002

Computed tomography diagnosis utilizing compressed image data: an ROC analysis using acute appendicitis as a model.

Using receiver-operating characteristic (ROC) methodology, the ability to diagnose acute appendicitis with computed tomography (CT) images displayed at varying levels of lossy compression was evaluated. Nine sequential images over the ileocecal region were obtained from 53 consecutive patients with right lower quadrant pain who were clinically suspected to have acute appendicitis. Thirty were proven surgically to have acute appendicitis, alternative diagnoses confirmed in 23. The image sets were subjected to a lossy wavelet-based compression algorithm "Embedded Predictive Wavelet Image Coder" (EPWIC). Compression levels were: none, 8:1, 16:1, and 24:1, resulting in 4 sets of images per patient. Image sets were randomized and evaluated separately by 4 body radiologists on a 1,024 x 768-pixel SVGA color PC monitor in 512 x 512 format. The readers were aware of the clinical suspicion of appendicitis but were unaware of the positive fraction of cases. Individual and combined reader ROC and c2 analyses of sensitivity, specificity, and accuracy were determined. For all readers, sensitivity decreases at 16:1 and 24:1 levels (P <0.01, P <0.001, respectively). Accuracy decreased at 24:1 levels (P <0.01). Specificity was unaffected. By ROC analysis there was statistically significantly decreased area under the curve at 24:1 levels (P <0.02) as compared with uncompressed images. Finite levels of lossy wavelet compression may be applied to CT images without compromising diagnostic performance.

Acute Disease↗
PubMed2002

Colorectal neoplasms: prospective comparison of thin-section low-dose multi-detector row CT colonography and conventional colonoscopy for detection.

PURPOSE: To prospectively compare thin-section low-dose multi-detector row computed tomographic (CT) colonography with conventional colonoscopy for the detection of colorectal neoplasms. MATERIALS AND METHODS: One hundred five patients underwent CT colonography immediately before colonoscopy. Supine and prone CT colonographic acquisitions to image the region during a 30-second breath hold were performed. CT colonographic images were prospectively interpreted for the presence, location, size, and morphologic features of polyps. The time of image interpretation was noted. Sensitivity, specificity, and positive and negative predictive values of CT colonography were calculated, with 95% CIs, by using colonoscopic findings as the reference standard. The weighted CT dose index was calculated on the basis of measurements in a standard body phantom. Effective dose was calculated by using commercially available software. RESULTS: Median CT data interpretation time was 12 minutes. One hundred thirty-two polyps in 59 patients were identified at colonoscopy; no polyps were detected in 46 patients. Sensitivities for detection of polyps smaller than 5 mm, 6-9 mm, and larger than 10 mm in diameter were 12% (11 of 91 polyps), 70% (19 of 27 polyps), and 93% (13 of 14 polyps), respectively. Estimated overall specificity was 97.7% (515 of 527 imaging results). The total weighted CT dose index for combined supine and prone CT colonography was 11.4 mGy. The effective doses for combined CT colonography were 5.0 mSv and 7.8 mSv for men and women, respectively. CONCLUSION: Low-dose multi-detector row CT colonography has excellent sensitivity and specificity for detection of colorectal neoplasms 10 mm and larger.

Aged↗
PubMed2002

Mesenteric adenitis: CT diagnosis of primary versus secondary causes, incidence, and clinical significance in pediatric and adult patients.

OBJECTIVE: Our objective was to determine the clinical significance of mesenteric adentitis when detected on CT. MATERIALS AND METHODS: Mesenteric adenitis was considered present if a cluster of three or more lymph nodes measuring 5 mm or greater each was present in the right lower quadrant mesentery. If no other abnormality was detected on CT, then mesenteric adenitis was considered primary. If a specific inflammatory process was detected in addition to the lymphadenopathy, then mesenteric adenitis was considered secondary. Patients with a known neoplasm or HIV infection were excluded. Three separate groups of patients were examined for the presence and cause of mesenteric adenitis. Group 1 consisted of 60 consecutive patients prospectively identified with mesenteric adenitis on CT examinations. Group 2 consisted of 60 consecutive patients undergoing abdominal and pelvic CT for evaluation of blunt or penetrating abdominal trauma. Group 3 consisted of 60 consecutive patients undergoing abdominal and pelvic CT with acute abdominal symptoms. In all patients, the indication for imaging was documented, and the size of the largest lymph node, when present, was measured. In patients with mesenteric adenitis, the CT findings, clinical history, and clinical or surgical follow-up were subsequently evaluated to determine the cause of mesenteric adenitis. RESULTS: In the 60 patients prospectively identified with CT findings of mesenteric adenitis (group 1), 18 (30%) of 60 had primary mesenteric adenitis. The remaining 42 patients (70%) had an associated inflammatory condition that was established on CT as the likely cause of mesenteric adenitis. Mesenteric adenitis was present in none (0%) of the 60 patients in group 2 and in five (8.3%) of 60 patients in group 3. CONCLUSION: The incidence of mesenteric adenitis in patients with and those without abdominal pain is low. When evidence of mesenteric adenitis is present on CT examinations, usually a specific diagnosis can be established as its cause.

Abdomen, Acute↗
PubMedDate not supplied

Filling defects at CT colonography: pseudo- and diminutive lesions (the good), polyps (the bad), flat lesions, masses, and carcinomas (the ugly).

Numerous filling defects may be detected in the colon during interpretation of data sets obtained with computed tomographic (CT) colonography. A series of 230 patients were evaluated with thin-section multidetector row CT colonography immediately before conventional colonoscopy. In all cases, the interpreting radiologist and gastroenterologist reviewed the imaging findings as well as the results of histologic analysis of biopsy specimens to determine the causes of filling defects. In many cases, the cause of a filling defect can be confidently determined at CT colonography by using combinations of two- and three-dimensional images. However, lesions will occasionally be indeterminate because of overlapping features and will require further evaluation with endoscopy. With knowledge of the morphologic and attenuation characteristics of the various filling defects in the colon, one should be able to differentiate those filling defects detected at CT colonography that require no further evaluation from those that require endoscopic interrogation.

Colonic Diseases↗